Multi-color patterned area rugs, wall rugs and other pile face materials have met with increasing commercial success, in the United States in the past few years. Traditionally such products are associated with various weaving processes using predyed yarns. Generally, skilled operators are required for these processes, productivity is low, and the products are expensive. In the tufting industry products of this kind are currently manufactured by means of the manually operated tufting gun, and in recent times by single and double needle control broadloom tufting machines. With single needle machines, although productivity is low and the products are expensive, a few companies have been able to make a commercial success of the operation. With double needle machines, productivity is high, but, in relation to the investment, the productivity traditionally associated with broadloom tufting is low. Even so, in the context of area rugs, these machines are capable of producing a limited variety of styles, at rates exceeding the capacity of the market for them. For these reasons these machines have not realized the future predicted for them.
Within the past fifteen years or so a very large carpet printing industry have grown up within the tufting industry. The carpet printing industry is geared, largely to broadloom manufacture and is not especially suitable for the pattern flexibility, variety of carpet textures and pattern sizes traditionally associated with high quality area rugs. Moreover, the capital investment incurred by these printing machines can only be generated by the enormous productivity of the broadloom industry.
There are numerous methods used for dye printing piled sheet materials, such as carpets, towels, animal furs and the like. These printing methods include flat screen printing, rotary screen printing, raised pattern roller printing, and "deep dye" printing and the Militron process.
The flat screen methods involve the use of screens which contact the surface of the sheet material. The dye pastes are applied to the top surfaces of the screens and forced through holes in the screens by magnetic squeegies, sponges or by suction from behind the sheet material. The screens are impenetrable in some areas and penetrable in the pattern areas where it is desired that dye pass to the sheet material.
The rotary screen is an adaptation of the flat screen, where the screen is formed in the shape of a cylinder. Roller processes involve the use of cylinders with patterned dye area raised out of the cylinder. The cylinders pick up dye on the faces of the raised dye area and transfer the dye to the sheet material, according to the pattern of the dye area, by rolling over the sheet material as the material moves along its length through the machinery.
The screen and roller processes are capable of printing low pile materials such as materials having pile in a quantity of about 8-14 oz./sq. yd., but they usually lack the ability to produce satisfactory results on heavier, high pile materials, as there is insufficient dye material passing through the screens and insufficient force exerted on the dye material to satisfactorily penetrate heavier weights of pile facing.
In the screen and roller dyeing processes, a separate screen or roller is required for each different color. This makes multi-color processes somewhat expensive, both because of duplication and because of mechanization and precision needed to index the separate color patterns. Another disadvantage of these processes is that they are limited in their pattern size, thus requiring several pattern components to form a single large sized pattern as might be associated with an area rug.
The "deep dye" process offers a method of applying all the colors of a pattern to the sheet material simultaneously. In this system, the printing stencil, comprising partitioning built up on a plate so as to form trough-like pattern elements into which various colors of dye solution is fed, is pressed mechanically upwardly against the downwardly facing pile of the sheet material. The equipment for performing the deep dye process is expensive to manufacture and to operate.
The Militron process is one uniquely capable of printing broadloom carpeting and area rugs. The process is based on the simultaneous injection of several colors of dye solution from a matrix of fine nozzles. Those nozzles in the matrix, which fall within the particular element of the pattern to be printed, are controlled so that they all pass the same color of dye solution together. The device is computer controlled, and the pattern is readily changed. The machine involves high capital investment and is not generally available; it is also, as far as known, limited to a comparatively narrow range of carpet pile textures.